Have an odd problem with the rear number plate light coming on for about 5 seconds then switching off, which would point towards a faulty relay. also get the occasional light error come up on the dashboard which then goes off .
Does anyone know which relay(s) affects the lighting?
Thanks

I am not familiar with the x250 Ducato, as mine is an earlier 2006 x244.

I assume that you mean that your number plate lamp is only staying on for about 5 minutes, when it should stay on. Not that the lamp is coming on at random.

I suspect that you a looking in the wrong area, as what you describe is not typical relay behaviour.

The light will probably be controlled by the BCM, which will have a programmed range of current to be drawn by the lamp. If the current drawn is deemed incorrect the BCM will raise an error warning, and if the current is seen as too high, perhaps switch off as a protective measure.

Check that correct wattage bulbs are fitted, to eliminate the above which is a guess on my part.

Also try new bulbs, to eliminate the possibility of an obscure bulb fault.

Thanks for that. The number plate light comes on for just 5 seconds then switches off. Have tested the voltage coming through and, while the light is on, it is in the range of 12 -13 volts, which should be ok. One of the tail lights also misbehaved in the same way for a while after I had taken the bulb out then put it back, but is now working again. Very odd. Also both number plate lights have been replaced and they both go off at the same time, but they are on a common circuit, so would expect that.

After much cursing and testing linking to sidelights, testing all the relays, the problem suddenly appeared. One of the bulbs put in at the garage was 10 watts (not 5). So, your answer was probably the correct one, as the bcm threw its rattle out the pram when is was asked to allow more power through that particular circuit.
Couple of led bulbs in and all seems hunky dory.
Thanks

Does anybody out there have a list of what relays are for what on a 2008 ducato. I cant find anywhere that identifies each one.

many thanks in advance

Hi,

The vehicle handbook for my 2006 x244 provides relay allocations.

Perhaps the x250 handbook is not as informative?

The following is quoted from the x250 training manual, which is available in the downloads section. The extract relates to the engine bay fusebox.


"RELAY A
T02 Main beam headlamps 20
T03 Horns 20
T05 Compressor 20
T06 Engine cooling electric fan (high speed) 30
T07 Engine cooling electric fan (low speed) 50
T08 Climate control unit 30
T09 Injection system (main) 30
T10 Fuel pump 20
T14 Fog lamps 20
T17 Windscreen washer pump 20
T19 Headlamp washing pump 30
T20 Spare -"


I assume that the numbers 20, 30, & 50 relate to the current rating of the relays. (Red = 30A, and the larger relay being of 50A rating.)

I believe there is variance by year, but you might find the following to be relevant to your vehicle:

In the downloads section of the forum, locate the Ducato section, and then "Fiat Ducato Training Manual".

There are links to two files in there; the download "Fiat Ducato 1st X250 Training Manual" contains descriptions of the fuse and relay positions and functions from page 117 on.